Conventionally, a transport ship (tanker), a floating storage unit, an above-ground storage facility, an underground storage facility and the like are used for transportation or storage of cryogenic liquids such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas) (for example, see Patent Literature 1 and Patent Literature 2).
In Patent Literature 1, a liquefied gas carrying vessel is disclosed that includes an outer tank that constitutes the hull of a ship, and a tank (inner tank) that is disposed in a self-standing state inside the outer tank. In Patent Literature 2, an above-ground LNG tank is disclosed that includes an outer tank that is disposed on the ground and an inner tank that is disposed in a self-standing state inside the outer tank. By adopting a configuration in which an inner tank that stores liquid cargo is independent from an outer tank in this manner, the inner tank can be protected from the external environment while allowing expansion and contraction (thermal expansion and thermal contraction) of the inner tank that accompanies changes in the temperature of the liquid cargo.